that's the explanation of the main Bitcoin glossary (we give it in "Rules"):
What is the Nonce number?
The Nonce number is a random number that is used by miners to generate a new Block. To generate a new valid Block miners have to try every single integer (from 1 to few billions) until they find the one (the Nonce) that will solve a difficult mathematical equation.
No one can predict the Nonce number: nothing is more provably fair than the magic Nonce!
https://en.bitcoin.it/wiki/NonceWhat are the Blocks?
Blocks are fundamental to the Bitcoin protocol as they contain the Bitcoin transactions.
Miners use dedicated hardware to solve difficult mathematical equations, running them with a different Nonce number each time, until a valid result is found and the new block is produced. On avarage the Bitcoin miners community finds a new Block every 10 minutes. Finding a block is not an easy or cheap task. It needs a lot of powerful dedicated hardware and big electricity consumption. There is no guarantee of being the miner that will find tha next valid Block either, as it is a trial and error process where computer power and luck play together.
That's why the miner (or the mining pool) that founds a new valid Block gets a nice reward: currently 25 new Bitcoins + all the fees attached to the transactions included in the Block he found.
https://en.bitcoin.it/wiki/blocksHow do the Bitcoin protocol and the Blockchain work?
The Bitcoin protocol and the Blockchain ledger have been designed and created by Satoshi Nakamoto in order to permanently record and securely store all the Bitcoin transactions on the Blockchain.
The Blockchain is the public ledger that contains all the Bitcoin transactions. Transactions, in order to be valid and not modifiable by fraudulent double spend attacks, have to be included inside a new valid block that will be attached to old ones in the Blockchain.
In simple words, when you do a Bitcoin payment, your transaction will show a "0" Confirmation status. This means that the Bitcoin network is aware of your transaction but the transaction has not been included and permanently stored in the Blockchain ledger yet. Once the transaction has been included in the next available valid block you will see that your transaction reaches "1" Confirmation. After 6 Confirmations (meaning 5 more blocks have been added to the Blockchain on top of the block that contains your transaction) the transaction can be considered perfectly valid and secured.
What does NONCE means by the way?